Spark plug heating and protecting attachment



July 21, 1953 Jl E. HOLM BERG Em. SPARK PLUG HEATING AND'PKOTECTING ATTACl -MENT Filed Febie, 1950 INVENTOR. 95 5? Patented July 21, 1953 SPARK PLUG HEATING AND PROTECTING ATTACHMENT John E. Holmberg' and Alvin J. Gruener, Duluth, Minn.; said Gruener assignor to Michael F. Stoffel, Minneapolis, Minn.

Application February 6, 1950, Serial No. 142,624

4 Claims.

This invention relates to an attachment for use on the spark plugs of internal combustion engines, such as are used in automobiles, and more par ticularly to a heating and protecting device for spark plugs.

A primary object of the invention is to provide an attachment which can be readily attached to and detached from a spark plug while in its operating position on an internal combustion engine, and which includes an electric heating element which is positioned adjacent the metallic base portion of the spark plug, so that energization of the heating element will warm the base of the spark plug and thereby the electrodes of the plug.

Another object of the invention is to provide a spark plug heating and protecting device as referred to above, wherein the device is formed in the shape of a hood which fits over the upper end of the spark plug and is held in place by the nut or other means which fastens on the upper end of the central electrode of the spark plug to attach an ignition wire thereto.

Still another object of the invention is to provide a spark plug attachment of the type referred to above wherein the device is in the form of a hood comprised of two portions, one of which fits about the lower metallic portion of the spark plug and has an upper section of reduced diameter, and an upper hood portion which fits about the section of reduced diameter in a telescoping manner, the upper portion being the one which fits about the upper end of the central electrode of the spark plug. This object also includes the provision of a spring between the upper and lower portions of the hood for urging these portions away from each other, thereby holding the lower portion of the hood firmly in place on the spark plug, and assuring that there will be no rattling or other inconvenience as a result of the bumping of the automobile.

The invention is of great benefit to motorists during cold weather, and greatly facilitates the starting of automobiles during such weather. By preheating the spark plug and the surrounding part of the motor head or motor block, the gasoline will be ignited practically as soon as the engine is turned over by the starter, and the battery is relieved of much of the heavy duty imposed on it during cold weather starting. The heating of the spark plug melts any frost from the electrode points and dries these points so that there will be no shorting during starting.

Use of the invention also assists in keeping the spark plug electrode points clean, for if the'plug ispreheated at the time of starting, any oil which has accumulated on the points will be burned immediately with the gasoline fed into the cylinder.

In addition to the advantages of the invention in facilitating quick starting, saving wear and tear on the battery, and keeping the spark plugs clean so that they will not have to be removed for cleaning so often, the invention provides an overall protection for spark plugs and keeps the porcelain insulation dry.

The above objects and advantages of the invention will be readily apparent from a study of the following specification, taken in conjunction with the accompanying drawing, in which:

Fig. 1 is a side elevational view of a heating and protecting device made in accordance with a preferred embodiment of the invention and mounted on a spark plug;

Fig. 2 is a longitudinal sectional view through the device shown in Fig. 1;

Fig. 3 is a cross sectional View taken on line 33 of Fig. 2; and

Fig. 4 is an exploded perspective view of the attachment shown in Fig. 1.

Referring now to the drawing, the embodiment of the invention shown therein will be described in relation to a spark plug shown in broken lines in Figs. 1 and 2, and comprising the usual metallic base I!) having a threaded lower end portion H which is screwed into the motor head or block, and is thereby electrically grounded as has been shown diagrammatically at 8. The metal base ll] of the spark plug has an enlarged upper portion l2 which is multi-sided, for example, hexagonal, to facilitate installation and removal of the plug by use of a wrench. Above the portion [2, a central electrode extends upwardly a considerable distance above the base of the plug, and a portion of this electrode is shown at l3. The upper end of this electrode is threaded or provided with other suitable configuration for receiving a nut M or other suitable means for attaching an ignition wire. The ignition wire may be attached below the nut M so that tightening of the nut would retain the wire in place, or the wire could be attached to the upper end of nut M by means of a well known resilient clamping device (not shown). The central electrode I3 is held in place and insulated from the metal base of the spark plug by insulation within the base which is not shown, and by an insulating body I5 which has an upper end surface against which nut l4 may bear.

The attachment which comprises the invention is shown in the drawings in a preferred embodiment, although it is to be understood that departures from the construction shown in the drawings can be made without departing from the inventive concept. The device comprises a hood which is divided into upper and lower portions, l8 and !9, respectively. This hood is made of any suitable insulating material, which is also somewhat heat resistant, as for example, porcelain or various synthetic plastic materials such as those of a thermo-setting nature.

The lower portion of the hood has a rounded exterior, and its interior is dimensioned so as to fit snugly about the flat-sided portion of the base of the spark plug. The lower base portion 19 has a flat surface 20 which faces upwardly and is annular in configuration. Immediately inwardly of this fiat surface, the lower hood extends upwardly to form an upper section 2! which is of reduced diameter.

Near the lower end of hood portion 19, an electric heating element 22 is mounted about the interior wall of the hood at a position such that it will lie adjacent the metal base portion of the spark plug when the hood is mounted in place. The heating element 22 may be in the form of a helix, or in any other suitable form. One end of the element is connected to a metal plate 23 mounted in the inner wall of the hood portion [9 so as to make a firm contact with the metal base of the spark plug, as for instance, at the fiat-sided portion :2. This provides a ground connection for one end of the heating element. The other end of the heating element 22 is attached to a wire 24 which is positioned within the walls of the hood portion 19 and extends into an integral arm 25 formed on the hood portion it. Near the end of arm 25, wire 24 is attached to a threaded post 26 which carries a nut 2? by means of which a wire 28 leading to a switch 29 and a source of current 39, may be attached to wire 24. Switch 25] may be located at any convenient place, such as on the dashboard of the automobile.

The upper portion !8 of the hood is dimensioned at its lower end to fit about the section 2| of hood portion l9, and at its upper end, portion 58 is of diminished diameter, and is provided with a central opening 33 which fits over the upper end of the electrode I3. The opening 33 is of smaller diameter than the nut Hi, so that by tightening the nut about the upper end of hood portion i8, as shown in Fig. 2, this hood portion will be held firmly in place. As will be pointed out presently, this also holds the lower portion of the hood in place.

For convenience and greater strength, the eX- treme upper end part of hood portion [8 may be in the form of a metal washer shown at 34, and this washer will then contain the opening 33 which has just been referred to. This washer will, of course, be attached rigidly to the upper hood portion IS.

A coil or other spring 35 is mounted about the upper section 2! of hood portion 19 so as to rest on the fiat surface 29, and when the upper hood portion !8 is mounted in telescoping relation with this upper section 2!, spring 36 is compressed and the two hood portions I8 and 19 are urged apart.

In mounting one of the heating and protective devices of my invention on a spark plug, it is simply necessary first to place the lower portion 19 over the upper end of the spark plug and to push it downwardly until it fits snugly about the metal base portion of the plug, as is shown in Fig. 2. Spring 36 is then placed on surface 20,

and upper portion l8 of the hood is then pushed downwardly over the upper end of the spark plug with the upper end of central electrode pole i3 passing through opening 33. Nut M is then screwed into place, and as it is screwed downwardly, spring 36 is compressed and a tight fit of all of the elements is assured. The reverse of this procedure is followed when the device is removed.

In connection with the attachment and detachment of the device as just described, it is important to note that it is not necessary to remove the spark plug in order to attach or detach the heating and protective device, so that use of the device is very simple.

In operation, with protecting and heating devices, according to the invention, mounted on the spark plugs of a vehicle and connected as described to a single switch 29, which may be of the spring push-button type, on the dashboard of the automobile, it is only necessary for the driver to operate the switch for a few seconds before starting, depending upon the temperature conditions, and if he then turns on the ignition and presses the starter, starting will be practically instantaneous. Once the engine is started, it will not be necessary to continue the heating of the spark plug, and switch 29 can be released by the driver.

The heating element 22 can be made in various sizes, in various shapes, and can be made for various operating voltages, depending upon the installation which is intended.

We wish it to be understood that the embodiment which we have described is only a preferred embodiment of the invention, and that numerous deviations from this embodiment can be made without departing from the inventive concept. It is our intention to cover by our patent all embodiments of the invention falling within the scope of the appended claims, and outside of the prior art.

We claim:

1. A heating and protecting device for spark plugs of the type having a metal base portion and a central terminal pole at the upper end for receiving an attaching device for an ignition wire, comprising a lower hood portion adapted to slip over the upper end of a spark plug and to fit closely about said metal base portion, an electric heating element carried by said lower hood portion and located adjacent said metal base portion when said lower hood portion is mounted on a spark plug, said lower hood portion having a flat upwardly facing surface and an upwardly extending section of reduced diameter lying above said surface, an upper hood portion fitting about said upwardly extending section in telescoping manner with its lower edge opposite said surface, said upper hood portion having a portion of diminished diameter at its upper end provided with an opening to fit over said central terminal pole below said attaching device, whereby said hood is held securely but removably in place, and a coil spring positioned about said upwardly extending section and compressed between said surface and said edge when said hood is in operating position.

2. A heating and protecting device as set forth in claim 1 in which the portion of said hood of diminished diameter comprises a washer of relatively strong material carried by the upper hood portion at its upper end.

3. A heating and protecting device for spark plugs of the type having a metal base portion and a central terminal pole at the upper end for receiving an attaching device for an ignition wire, comprising a hood, including upper and lower portions, of insulating material adapted to slip over the upper end of a spark plug so as to enclose substantially the entire plug and to fit closely about said metal base portion, a helical coil electric heating element carried by the lower portion of said hood and extending around the internal circumference of said hood so as to be located adjacent said metal base when said hood is mounted over a spark plug, the upper portion of said hood having a lower part thereof of larger diameter than the upper part of said lower portion so as to fit about the upper part of said lower portion in a telescoping manner, said hood having an opening in said upper portion to fit over said central terminal pole below said attachin device, whereby said hood portions are held securely but removably in place.

4. A heating and protecting device for spark plugs of the type having a metal base portion and a central terminal pole at the upper end for receiving an attaching device for an ignition wire, comprising a hood, including upper and lower portions, of insulating material adapted to slip over the upper end of a spark plug so as to enclose substantially the entire plug and to fit closely about said metal base portion, a helical coil electric heating element carried by the lower portion of said hood and extending around the 6 internal circumference of said hood so as to be located adjacent said metal base when said hood is mounted over a spark plug, the upper portion of said hood having a lower part thereof of larger diameter than the upper part of said lower portion so as to fit about the upper part of said 1ower portion in a telescoping manner, and resilient means connected between said upper and lower portions and urging said portions away from each other, said hood having an opening in said upper portion to fit over said central terminal pole below said attaching device, whereby said hood portions are held securely but removably in place.

JOHN E. HOLMBERG.

ALVIN J. GRUENER.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,465,935 Eastman a- Aug. 28, 1923 1,495,215 Williams May 27, 1924 1,805,040 Groves May 21, 1931 1,999,118 Simsack Apr. 23, 1935 2,190,765 Barr Feb. 20, 1940 2,300,294 Iavarone Oct. 27, 1942 FOREIGN PATENTS Number Country Date 645,850 Germany June 4, 1937 

